criticisms and suggestions; and to a number of other friends for reading and passing judgment upon my manuscript. NEW HAVEN, January 11, 1915. ALBERT G. KELLER. SOCIETAL EVOLUTION INTRODUCTION On a number of counts, the natural scientist is fairly an object of envy to the social scientist. The former deals with things, gets verification through repeated experiment, sets aside unreasonable prejudice by definite proof, attains such certainty as to justify prediction. The latter deals with the elusive human factor, may not deliberately experiment, faces what looks like impregnable prepossession and tradition at every turn, and cannot in general arrive at more than a high degree of probability. Furthermore, natural scientists have a way of climbing by standing on each other's shoulders, whereas social scientists, much like some philosophers and historians, seem to feel that they must each begin at the bottom, and start off by discrediting their forerunners. No doubt some such unlikeness in method lies implicit in the different nature of the two fields; |